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Stability, ranks, and the PhyloCode

100%

Lee M. S. Y., Skinner A.

Acta Palaeontologica Polonica

2007

tom 52

nr 3

Current codes of biological nomenclature define taxon names using types and ranks: the type determines the minimal membership of a named taxon, and the rank is supposed to determine its limits. Homo is “the taxon including the type species Homo sapiens that is assigned to the rank of genus”. However, there is no “genus concept” (analogous to a species concept), and thus no way of empirically determining the limits of a particular genus, even in the context of a single agreed phylogeny. The same problems also apply to higher taxa at all other ranks under current codes, leading to great taxonomic instability. All proposed objective criteria for determining membership of taxa at a particular rank (e.g., geological age, genetic divergence) are shown to be problematic. In contrast, the clades named by phylogenetic definitions are objective and stable. Node−based and branchbased definitions are most precise; however, apomorphybased definitions can be ambiguous due to difficulty in defining alternative character states, and optimisation uncertainty. A major benefit of ranks (information about relative nesting of taxa) can be achieved even more efficiently using standardised but rankless suffixes already widely used in phylogenetic taxonomy. Finally, in situations where the phylogeny is poorly known, phylogenetic nomenclature appears to be superior to the Linnean system. Phylogenetic nomenclature does not force one to officially name poorly corroborated groupings, whereas Linnean codes compel users to erect and name genera even when relevant supraspecific relationships are poorly known.

Relationship between dominance and antler cycle in white-tailed deer Odocoileus virginianus

100%

Bartos L., Miller K. V., Osborn D.

Acta Theriologica

2004

tom 49

nr 4

We tested the hypothesis that there is a negative correlation between rank and order of casting antlers in white-tailed deerOdocoileus virginianus (Zimmermann, 1780) and that dominant individuals will start antler regrowth and velvet shedding earlier than subordinates. We assessed dominance relationship among 14 bucks (1.5 to 7.5 years-of-age) confined in a 0.6 ha enclosure and related hierarchal position to timing of antler casting, initiation of antler regrowth, and initiation of velvet shedding. During 66 observation sessions we recorded 2833 agonistic interactions. Bucks developed an unstable hierarchy with relatively frequent changes in rank, particularly in the upper half of the hierarchy. Antler casting dates were positively correlated with age and wins and losses of agonistic encounters; correlations with body mass approached significance. When age was eliminated as a confounding factor by partial correlation, no significant relationship between antler casting date and other characteristics occurred, except losses. When body mass was eliminated by partial correlation, the relationship between casting date and losses was more pronounced. Timing of antler regrowth was negatively correlated with age, body mass, rank and wins, while positively correlated with losses. The start of velvet shedding was negatively correlated with rank position. Our results are in apparent contrast with previous studies. However, our experimental group contained more individuals in a confined area than is typical for the species. Whitetails may be more susceptible to social stress in captivity than more gregarious species such as red deer, resulting in variable responses to rank position.

Ograniczanie wyników

1 Acta Palaeontologica Polonica

1 Acta Theriologica

1 Bartos L.

1 Lee M. S. Y.

1 Miller K. V.

1 Osborn D.

1 Skinner A.

1 2007

1 2004

Wyniki wyszukiwania

Stability, ranks, and the PhyloCode

Relationship between dominance and antler cycle in white-tailed deer Odocoileus virginianus